1. Field of the Invention
The present invention generally relates to a method of and apparatus for making pellets comprised of several stringers and deck boards on both sides of the stringers, such pallets being hereinafter referred to as double-faced pallets. The present invention more particularly relates to a method and apparatus for making double-faced pallets wherein deckboards are first attached to one side of several stringers to form a half-pallet, thereafter the half-pallet assembly is inverted, and deckboards are applied to the opposite sides of the stringers to form a double-faced pallet.
2. Description of the Prior Art
U.S. Pat. Nos. 3,557,439 to Dykeman and 4,054,236 to Paxton illustrate prior art apparatus for assembling double-faced pallets. The Dykeman patent discloses an apparatus that utilizes two nailing machines that are each adapted to drive nails vertically downwardly and a transfer device that is disposed between the nailing machines. The transfer device is adapted to turn over a half-pallet formed by the first nailing machine so that it may be fed in an inverted orientation to the second nailing machine. In the Dykeman system, the upstream nailing machine includes a jig adapted to receive stringers and hold the stringers in place in the desired parallel relationship. Deckboards are manually placed on the stringers within the jig, and then the jig is moved into a nailing station where nails are driven downwardly through the deckboards to fasten the deckboards to the stringers.
The Paxton U.S. Pat. No. 4,054,236 discloses an apparatus for making double-faced pallets which includes a single nailing machine and a conveyor that is adapted to concurrently support several stringers to which the bottom deckboards are attached and an inverted half-pallet assembly. Bottom deckboards are first attached to the several stringers at the nailing station and then the half-pallet assembly is returned to the deckboard loading position. The half-pallet is manually inverted at the loading position with the assistance of arcuate ramps that are adapted to lift one end of the half-pallet assembly from the conveyor on which the half-pallet is supported. After manually pivoting the half-pallet assembly and lowering it onto the pallet feeder of the nailing machine, the half-pallet assembly is advanced toward the nailing station and thereafter a further set of stringers is placed on the feeder conveyor. The Paxton U.S. Pat. No. 4,054,236 describes and claims a feeder conveyor that is adapted to support the empty stringers at a height such that the upper edges thereof to which the bottom deckboards are to be attached lies in the plane of the top edges of the stringers of the inverted half-pallet that is supported on the feed conveyor upstream from the empty stringers. The Paxton apparatus further includes a deckboard feeder adapted to automatically feed deckboards into nailing positions on the stringers. The apparatus of the Paxton machine is illustrated in trade literature published by S. W. F. Machinery, Inc. of Sanger, Calif. This trade literature, which is entitled "The Big Breakthrough in Faster Pallet Production", illustrates how two operators on opposite sides of the half-pallet turn the half-pallet which has been pivoted upwardly by arcuate ramps; the operators guide the pallet back into flight bars of the feeder conveyor with the bottom side down to return it to the deckboard nailing position.